Gas discharge tube counting arrangement



Jan. 27, 1953 A. J. MULLARKEY GAS DISCHARGE TUBE COUNTING ARRANGEMENT 3Sheets-Sheet 1 Filed June 4, 1949 INVENTOR ALFRED J. MULLARKEY uni IATTORNEY .I'an. 27,1953 MULLARKEY 4 2,626,751

GAS DISCHARGE TUBE COUNTING ARRANGEMENT Filed June 4 1949 :s'shees-sheet 2 INVENTOR ALFRED a, MULLARKEX ATTORNEY 3 Sheets-Sheet 3 -ANWJan. 27, 195-3 Filed June 4, 1949 INVENTOR ALFRED J. MULLAFKE) ATTORN EYing a tube at that position fired as Patented Jan. 27, 1953 GAS DISCIIARGE TUBE COUNTING ARRANGEMENT Alfred John Mullarkey, London, England,assignor to International Standard Electric Corporation, New York, N.Y.,

, Delaware a corporation of Application June 4, 1949, Serial No. 97,140

In Great Britain June 11, 1948 Claims. (Cl. 235-43) 1. The inventionrelates to counting arrangements.

Electric tube counting rings are well known in the art and are widelyused. The rings incorporate cold cathode gas discharge tubes, one ex--ample of such rings being found in British Patent No; 567,863 or mayalternatively use thyratrons in the manner disclosed. in the paperpresented by C. Wynn-Williams to the Royal Society in 1931 (Proc. R. S.1931 pages 295-309).

The object of the present invention is to provide improvements in gasdischarge tube counting arrangements, especially by the provision ofreversibility in the operation of the circuits.

One application of reversible counting arrangements is to railway axlecounting equipment. Such equipment necessitates the employment ofcounting apparatus operable to receive signals initiated by axlespassing in and out of a track section, signal transmitting means beingsituated at both ends of the section. The significance of the signals isof two kinds, 1. e., in" and out," and the counter is required tomemorise" the difference between the total of each kind received so thatwhen that difference disappears, i. e., when an equal number or axleshave entered and left the section and it is therefore unoccupied, anindication or a transmission of an output signal recording the fact isneeded.

The invention provides a gas-discharge tube chain circuit to which isapplied pulses from two sources. Pulses from one source effect thefiring of a succession of the tubes one at a time in one directionwhilst pulses from the other cause the firing of a succession of tubesone at a time in the opposite direction. The chain of tubes is completedinto ring formation so that endless sequential operation is obtainable.The tubes may either be arranged in pairs so that one particular tube ofa pair fires when the order of firing is in one direction and the otherwhen the order is opposite, or the tubes may be so constructed that thesame succession of tubes is able to be used whatever the direction ofthe sequential firing. A plurality of tube counting rings as outlinedabove and having different numbers of tubes per ring canbeinterconnected as a difierential counting device; In this case, pulsesfrom the two sources are fed in common to all the rings and eachoperates as already described. One position in each ring-having a singletube or a tube pair thereat is designated the home position and anoutput may be taken from there whenever that particular ring has reachedthe stage of hava result of segas discharge tube 2 quential operation oftubes. Simultaneous output pulses irom all home positions are recordedand such a condition indicates that equal numbers of pulses have beenreceived from both sources provided always that the pulses from onesource do not exceed those from the other by a number equal to orgreater than the product.

of the numbers of tubes, or tube pairs, in the various interconnectedrings.

The invention will now be particularly described with reference tocertain embodiments shown in the accompanying drawings in which- Fig. lshows'the circuit of a cold cathode gas discharge tube counted in whichthree electrode tubes are used whilst,

Fig. 2 is a schematic diagram of a similar counter which uses fourelectrode tubes, thus providing economy in the number of tubes.

Fig. 3 shows diagrammatically a differential counter for use withrailway axle counting equipment which employs a number of difierent sizering counters each being of the kind shown in either Fig. 1 or Fig. 2.

Fig. 4 is a safeguard circuit desirable for use with the differentialcounter of Fig. 3.

Considering first the three-position ring counter shown in Fig. 1, itwill be seen that at each of the positions I, 2 and 3 there are two,threeelectrode tubes lettered a and b respectively. The position I willbe referred to as the home position. The grid electrodes of the a tubesare connected by series resistance-capacity circuits t to a common lead5. The grid electrodes of the b tubes are connected by similarresistance'capacity circuits 6 to a common lead i. The tubes at the samepositions have their cathodes commoned, negative high voltage supplybeing provided to them over lead 8. The positive high voltage is led vialead 9 through a dropping resistance H) to the anodes of all the tubes.

Turning to the operation of the ring circuit it is to be understood thatone of the tubes at the position I, say la, is initially in adischarging condition. Means for ensuring this are not shown on thedrawing but are simple and well known. With la fired, a potential isapplied to the grid of tube in. via a centre-tap on the resistor of thecathode circuit I I but this is insufficiently large to cause the tube2a to strike. A positive pulse received over lead 5 however, willfurther raise the potential oi the grid of tube 2a to a value sufflcientto fire it and a discharge will commence.

the potential across the tube la is therefore reduced. It falls to avalue below the maintaining potential required for the tube and tube laex.

tinguishe's. The current through resistance il failing, the anodepotential will rise. Due to the chargebeing maintained on the condenserof the network ii of position I, the priming voltage is retained at thegrid of tube 2a so ensuring that the discharge which had commenced inthat tube is prolonged. Further pulses on lead effect the firing of thenext a tube in each case, Ia firing off the first of such further pulsesand 2a being extinguished. The position occupied by the discharging tubecan be made to travel continually in a clockwise direction around thering in response to continual pulses on lead 5, la following 3a, 2afollowing la, and so on.

The reversing feature is now to be considered. Assume that clockwisecounting has resulted in tube 3a being fired. From tube to, a potentialis applied to the grids of tubes la and 2b. If now, instead of the nextpulse being applied to lead 5 it is applied to lead I, tube 2b will bestruck instead of la. Further pulses on lead 1 result in anti-clockwiseoperation of the counting ring on the b tubes.

It is clear that the above description while referring in detail to athree-position ring counter, could apply to counters of this type havingany number of positions. The circuit may be arranged to give anindication or transmit a signal whenever a home" position tube isdischarging. In applications wherein a small number of signals only arereceived from two sources, such a reversible ring counter is able todetermine e. g., whenever an equal number of signals has been receivedfrom both sources.

A circuit giving corresponding results but with less equipment is shownin Fig. 2, use being made there of four-electrode cold cathode gasdischarge tubes in order to provide the desired economy. Once more, byway of example only, a three-position ring counter is to be considered,but in this case we have one .tube per position and not two. as before.Three tubes i2. i3 and H are shown and it will be seen that parts of thecircuit in this figure which correspond directly in their function toparts in Fig. 1 have been similarly numbered. Considering that tube i2is the home" position tube and that at some instant tube i3 is firedwith the other two extinguished the operation thereafter in the twocases when either the next received pulse is along lead 5 or lead I willbe described.

Tube l3 being in a discharging condition, a potential will be applied tothe left-hand grid electrode of tube id but this will be insufficient tocause striking. A pulse received now along lead 5 ha no effect on tubeIt at all, tube i3 is already discharging and is therefore not affectedbut the continuation of the potential already on the left-hand grid oftube i4 and the received pulse causes tube H to strike. Tube i 3 isthereupon extinguished.

It will be observed that the cathode connection to the left-handelectrode of tube I4 is also taken to the right-hand electrode of tubei2. The pulse being received over lead I would have been applied overthe circuit 6 to cause tube i2 to strike, hence reversing the operationof the counting ring. This counting ring has similar possibilities ofapplication to that described with reference to Fig. 1; performing thesame function but economising in the number of cold cathode gas tubesemployed.

One application of these reversible counting rings is to railway axlecounting equipment as has been mentioned. The number of axles enteringand leaving a track section as a train passes through it. is, of course,fairly large as a rule. The reversible counter principle is required butimpracticable complication would normally result (certainly in longtrack sections) from using a counter according to Fig. 1 or Fig. 2 witha number of positions slightly larger than the greatest number of axlesto be dealt with, i. e.with the longest train.

To. overcome this problem the invention provides for the employment oftwo or more rings in co-operation. This provision will be understood bythe following description relating to Fig. 3.

The two leads 5 and l are taken to three ring counters IS, IS and I!(either of the three-electrode or four-electrode tube type or of anothertype to be mentioned later). In the example being considered, ring i5has five positions. ring i6, seven positions and ring I! nine positions.Assuming that the three rings all start from their respective homepcsitions and that a chain circuit ensures that an indication is givenby some means whenever all three rings are at their home positions. Suchindication may be arranged to result in the Track Unoccupied" conditionbeing shown in the signal cabin. A train entering the section willresult in pulse signals being received say along 5, each representativeof the entry of one axle. Each ring counter will step from its homeposition and it will be obvious that if signals were only received onthis lead all three rings would not reach their home positionssimultaneously until 5 7 9=3l5 axles had been counted. Such a number isconsidered to be periectly adequate for normal railway working. If. insome special case, a larger number needed to be catered for, then ringswith other numbers of positions could be used, e. g. 7 9 11=693.

Apparatus immediately prior to this counter is incorporated in axlecounting equipment to ensure that in-and-out counting pulses are nottransmitted along leads 5 and 1 simultaneously. Such apparatus may be ofthe kind disclosed and claimed in my copending application filed April29, 1949 and bearing Serial No. 90,315.

When the numbers of in-and-out-counting pulses are equal, i. e., when atrain has passed into and out of a section, the three ring counters willall restore to their home positions and the signal cabin indicator whichhas been showing "Track Occupied" since the first in-counting pulse wasreceived is also cleared.

To ensure Right Side Failure principles on the counter, which arefundamental requirements in railway signalling equipment, the followingconditions must be fulfilled:

(1) To prove all three ring counters are, or are not, in the homeposition.

(2) To prove all three ring counters have left the home position beforeTrack Unoccupied" indication is again given, i. e., to prove that noring has stuck.

I The safeguarding circuits are shown in Fig. 4 and it will be seen thatthe cathode voltage from every home position tube of the three ringcounters indicated at i 8, i9, 20 is brought out via a high resistance2! to a common point which is taken to negative potential via aresistance 22. This forms a potential dividing network the total voltagebeing fed to the grids of tubes 23 and 24. Tube 23 is biased to such avalue that relay 25 will operate only when all three ring counters arein the home position. The operation of relay 25 proves that the countersare in the home position.

It must be noticed that initially, relay 26 must be operated manually.

Tube 24' counters have left the home position, operate;

On receipt or the first in-counting pulse, all three ring counters stepof! from the home posi-, tion, which causes the release of relay 2! andthe operation of relay 26. Contacts of both relays 25 and 26 will beopened and the indicator 21 gives the Track Occupied condition. TheTrack Occupied" indication can only be given when relay 26 hasre-operated and this can only happen when relay 26 has released, whichproves that all ring counters have moved away from the home position andhave returned to the home position.

It will be noticed that relay 26 is held operated over contacts 253,263. This prevents the relay from releasing every time one home positionis is biassed so that when all three ringrelay 26 will one of thesources to the first electrodes of the tubes in each ringsimultaneously, means to apply the pulses. received from the othersource to the second electrodes of the tubes in each ringsimultaneously- Said circuit means-extinguishing the operation of thepreceding tube upon the subsequent firing of a conditioned tube in eachring,

and indicating means coupled to the conditioning means or a particulartube of each of said rings,

operable only when each of said particular tubes have firedsimultaneously, whereby the pulses rea reverse direction electric pulsesreceived from a reached. The release of relay 26 will only take placewhen relay operates. I.

Although the use of cold cathode gas discharge tubes is preferred theinvention is not limited to the employment or such tubes only. Inaddition the diflerential pflunter described above which incorporatestwo or more ring counting chains may have each of such chains in theform of single tubes e. g., as disclosed and claimed in the copendingapplication of D. S. Ridler, filed June to, 1949 bearing Serial No.100,462.

What is claimed is:

1. An electronic ring for differentially counting electric pulsesreceived from two sources comprising a train of electronic tubes, eachtube having an anode, a cathode and a control electrode, circuit meansto allow the conductive operation of any one of the tubes, said meanscommon to said anodes, means coupled to said cathodes and certain ofsaid control electrodes to fire successively tubes in a given directionalong the said train form the said first operating tube on receipt ofpulses from one source, means coupled to said cathodes and other of saidcontrol electrodes to fire successively tubes in the reverse directionalong the said train on receipt of pulses from the other source, saidcircuit means extinguishing the preceding operating tube when asubsequent tube is fired, and means to interconnect the tubes at eachend of the train to allow successive tube firings to proceedrepetitively around the train in either direction.

2. A device for counting electric pulses according to claim 1 whereinthe said circuit means to allow the operation of any one of the tubesand to extinguish the preceding operating tube when a subsequent tube isfired comprises a resistor common to the anodes of the tubes in the saidtrain.

3. A device for differentially counting electric pulses received fromtwo sources comprising a plurality of counting rings, each ring having asequence of a different number of tubes, each tube having an anode, acathode a first and a second control electrode, circuit means to allowthe conductive operation of any one of the said tubes in each ring, saidmeans common to the anodes of the tubes in each ring, means coupled tothe cathodes of the tubes in each ring to condition the first electrodeof a tube contiguous on one side of a conducting tube and the secondelectrode of a tube contiguous on the reverse side of said conductingtube, to fire upon receipt of an electric pulse at the said conditionedelectrodes, means to apply the pulses received from second source ofpulses comprising a counting train of electronictubes arranged in pairs,each otsaid tubes having-an anode, a cathode and a control electrode,each of said tube pairs havin a first and a second tube which togetherconstitute a single counting position of said train, circuit means toallow the conductive operation of any one of the tubes, said meanscommon to said anodes, means coupled to the cathodes of each pair oftubes tocondition the first tube of the tube pair contiguous on one sideof a conducting tube and the second tube in the tube pair contiguous onthe reverse side of said conducting tube to fire on receipt of anelectric pulse upon the control electrode at the respective tubes, meansto apply the pulses received from one of the said sources to the controlelectrodes of each of the first tubes of each tube pair, means to applythe pulses received from the other of said sources to the controlelectrodes of each of the second tubes of each tube pair, said circuitmeans extinguishing the operation of a preceding tube upon thesubsequent firing oi a conditioned tube. whereby received pulses fromone of the sources will sequentially fire the first tubes of each pairin a given direction along the train from the said first operating tubeand received pulses from the other source will sequentially fire thesecond tubes of each pair in the reverse direction.

5. A device for counting electric pulses according to claim 4, whereinsaid means to condi tion for firing the first tube of the next tube paircontiguous on one side of a conducting tube and the second tube of thenext tube pair contiguous on the reverse side of said conducting tubeoomprises, a resistance in the cathode circuit of each tube pair andconnections from the cathode circuit of each tube pair to the controlelectrode of the first tube of the contiguous tube pair on one side andto the control electrode of the second tube of the contiguous tube pairon the reverse side.

6. A device for counting electric pulses received from a first source ofpulses and for counting in a reverse direction electric pulses receivedfrom a second source of pulses comprising a train of gas dischargetubes, each tube having a cathode. an anode, a first and second controlelectrode, circuit means to allow the conductive operation of any one ofsaid tubes, said means common to said anodes, means coupled to thecathodes of each of said tubes to condition for firing the first controlelectrode of a tube contiguous to 7 operable upon receipt saidconditioned control electrode, means to apply the pulses received iromone of the sources to the first control electrodes 01 the tubes in the,train, meansto apply the pulses received irom the other source to thesecond control electrodes of the tubes in the train, said circuit meansextinguishing the operation 01' the preceding tube upon the subsequentfiring 01' a conditioned tube, whereby the pulses received from thefirst source successively fire the tubes along the train in a givendirection from the said first conducting tube and the pulses receivedfrom a second source successively fire the tubes along the reversedirection.

- 7. A device for counting electric pulses according to claim 6, whereinsaid circuit means to allow the conductive operation or any one of saidtubes and to extinguish the operation of a preceding tube upon thesubsequent firing a conditioned tube comprises a resistor common to theanodes oi the tubes in'the said train, and wherein the said means tocondition the first control electrodes of the tubecontiguous to saidconducting tube on one, side and the second control electrode of thetube contiguous to said conducting tube on the reverse side comprises aseparate resistor in the cathode circuit 01' each of the tubes in thetrain and connections from the positive side of each resistor to thefirst control electrode of the tube contiguous to said conducting tubeon one side and to the second control electrode of the tube contiguousto said conducting tube on the reverse side.

8. A device for counting electric pulses received from a first source ofpulses and for counting in a reverse direction electric pulses receivedfrom a second source of pulses comprising a plurality of counting trainsof electronic tubes, each tube having an anode, a cathode and a controlelectrode, each train having circuit means to allow the operation of anyone of the tubes in the train, said means common to the anodes of thetubes of said train, means coupled to said cathodes and certain of saidcontrol electrodes to fire successively tubes in a given direction alongthe said train from the said operating tube upon the simultaneousreceipt by said certain control electrodes of pulses from said firstsource, means coupled to said cathode and other of said controlelectrodes to fire successively tubes in the reverse direction along thesaid train upon the simultaneous receipt by said other controlelectrodes of pulses Iromsaid second source, said circuit meansextinguishingthe preceding operating tube when a subsequent tube isfired, means to interconnect the tubes on each end of a train to allowsuccessive tube firings to proceed repetitively around the train ineither direction, each of said trains firing simultaneously along thesame direction on the receipt of each pulse, said device having adifferent number of tubes in each of said counting trains.

9. A device for difierentially counting electric pulses received fromtwo sources comprising a plurality of counting rings, each ring havingelectronic tubes arranged in pairs of first and second tubes, each tubehaving an anode, a cathode and a control electrode, each tube pairconstituting a single counting position of the said ring, circuit meansto allow the conductive operation 01' any one of the tubes in each ring,said of electric pulses at the meanscommon to the anodes of each of thetubes comprising a ring, means coupled to the cathode of each tube pairin each ring to condition for firing the first tube of the tube paircontiguous on 5 one side of a conducting tube and the second tube in thetube pair contiguous on the reverse side of said conducting tube uponthe simultaneous receipt of an electric pulse upon the control electrodeat .the respective tubes, means to simultaneously apple the pulsesreceived from one source to the control electrode or the first tubes ofeach pair in each ring simultaneously, means to simultaneously apply thepulses received from the other source to the control electrodes of the 1second tubes of each pair in each ring simultaneously, said circuitmeans extinguishing in each ring the operation 01' a preceding tube uponthe subsequent firing 01' a conditioned tube, whereby received pulsesfrom one of the sources will sequentially fire the first tube of eachtube pair in a given direction along each ring and received pulses fromthe other source will sequentially fire the second tubes of each pair inthe reverse direction around each ring, the said device having adifferent number of counting positions in each ring.

10. A device for counting electric pulses received from a first sourceof pulses and for counting in a reverse direction electric pulsesreceived from a second source of pulses comprising a plurality ofdischarge paths arranged in a train, discharge control means associatedwith each of said paths, certain of said control means coupled to saidfirst pulse source and other of said control means coupled to saidsecond pulse source, single circuit means common to said discharge pathsto allow conductive operation of but one of said discharge paths at atime, separate means coupling each of said discharge paths with thedischarge control means associated with the discharge paths in saidtrain adjacent each said discharge path, said circuit means common tosaid discharge paths adapted to extinguish the conductive operation of apreceding path upon the conductive operation of a conditioned path,whereby received pulses from said first source will cause sequentialconductive operation of the discharge paths in said train in a givendirection and received pulses from said second source will causesequential conductive operation of the discharge paths in said train inthe reverse direction.

ALFRED JOHN MULLARKEY.

REFERENCES CITED 5' The following references are of record in the fileof this patent:

UNITED STATES PATENTS Regener Rev. Sc. Inst, Oct. 1946, volume 17, pages375-376.

Differential Counting with Reversible Decade Counting Circuits, Rev. Sc.Inst.,'June 1949,

pages 424-425.

